Buffer Overflow Intro. ©2002, Jedidiah R. Crandall, Susan L. Gerhart, Jan G. Hogle.  http://sfsecurity.pr.erau.edu
Really! The mailroom is just like a modern computer on another scale!

In fact, the only real difference between the mailroom and a real computer is that a real computer might have dozens of hands (called registers) and the memory might have millions of mailboxes (called words). 

Consequently, a pointer to a word in a computer’s memory might need to be in the billions and therefore you would need 4 bytes of memory to store it.